Question about Union strategy in Virginia during the Civil War

ben0628

Banned
As we all know, more often than not, the Army of the Potomac decided to commit to a overland campaign in Virginia. This meant the Union Army would have to cross numerous rivers that went from west to east, which provided the Confederate Army a major defensive bonus. At the same time, the Union army would always send a small force to try and capture the strategically important Shenandoah Valley, however this would usually result in failure.

So here is my question. Would it not have been smarter to leave a semi-large (say 30 to 40 thousand men) to guard D.C. and everything North of the Potomac while sending the vast majority of the Army of the Potomac into the Shenandoah Valley? Doing so would not only provide ample protection for the Union capital, but it would also allow the Union army to use the bulk of its force to capture the strategically important valley, as well as bypass every single major river in Virginia and approach Richmond from the west instead of North (thus preventing the Confederate army from using its defensive terrain). Does this not make sense?
 
As we all know, more often than not, the Army of the Potomac decided to commit to a overland campaign in Virginia. This meant the Union Army would have to cross numerous rivers that went from west to east, which provided the Confederate Army a major defensive bonus. At the same time, the Union army would always send a small force to try and capture the strategically important Shenandoah Valley, however this would usually result in failure.

So here is my question. Would it not have been smarter to leave a semi-large (say 30 to 40 thousand men) to guard D.C. and everything North of the Potomac while sending the vast majority of the Army of the Potomac into the Shenandoah Valley? Doing so would not only provide ample protection for the Union capital, but it would also allow the Union army to use the bulk of its force to capture the strategically important valley, as well as bypass every single major river in Virginia and approach Richmond from the west instead of North (thus preventing the Confederate army from using its defensive terrain). Does this not make sense?
The answer lies in logistics. Looking at a map of railroads in Virginia, there are no major railroad going down the Shenandoah Valley. Large armies in the American Civil War had to be supplied either through rivers or railroads over extended periods of time.

Indeed, there were railroads in the Valley like the Winchester & Potomac railroad (ran from Winchester to Harpers Ferry via Charles Town, a distance of 32 miles) and the Manassas Gap Railroad (ran 78 miles from near Mt. Jackson via Strasburg, Front Royal, and Manassas Gap to Manassas Junction where it joined the Orange & Alexandria Railroad). However, by 1862, both railroads had been thoroughly dismantled. In 1864, there was some attempt by the Union army to repair the railroads but partisan activity led to the effort being abandoned.

In addition, any march down the Shenandoah Valley would also require detaching a large number of troops to guard the route along Blue Ridge from raids and partisan attacks.

As a result, the Union could only realistically use a relatively small force (~30,000 man force) to invade the Valley. There were only three routes the Army of the Potomac could realistically take:
a) The Richmond, Fredericksburg, and Potomac (RF&P) Railroad which ran from the north past Aquia Landing, a key Union supply base when it was held by the Federal troops, through Fredericksburg and directly towards Richmond. Aside from being the most direct route, it also could handle the most volume of the two railroad routes. This was the route taken by Hooker and Burnside.

b) The Orange and Alexandria Railroad. However, it handled notably less volume than the RF&P, and had another notable disadvantage; it led away from Richmond. Charlottesville was about as close as it could lead towards Richmond. The Lincoln administration liked this route because it did keep the AotP more or less between Lee and D.C. Most of the AotP generals, particularly McClellan's adherents (for example Sedgwick), disliked this route however.

c) The Peninsula-James River route.
McClellan and Sedgwick considered it the "true" line of operation to take Richmond; this route enabled the Union army to be secure on the flanks, and to be supplied by sea from the Union navy. However, the Peninsula route was inherently somewhat vulnerable to being bottle-necked, and just as importantly, McClellan's failed campaign using this route poisoned it politically in the eyes of the Republicans. Still, strictly in military terms, McClellan was quite probably correct to see this as the best route.
 
Another large issue is that the Confederate army has a "clear shot on Washington" (least in the minds of the government officials) with no major army in its way. Arnold brought up most of the important points but you also have to consider that the Shenandoah was pretty heavily destroyed at that point, it wasn't the major farming area that it used to be with more then half the land burned so a good portion of supplies would need to be brought in on a railway that likely couldn't handle the load (I have no idea the tonnage that line could bring forth on a regular basis). That rail line would be exposed to raider and regular army activity too unless heavily guarded all along the line which would only continue to weaken the Union army in the area.

Another large thing to consider is that if the Union army needs to retreat from the Valley for whatever reason they only have one avenue to retreat back to Washington from. They can move east and go into West Virginia but that's a very dangerous situation to be in if you army is defeated in battle in a significant manner.
 
And the Union didn't commit to an overland Virginia campaign until McClellan's Peninsular Campaign fizzled out. Why they never tried something like that again is the bigger question than the Shenandoah Valley, IMO.
 
And the Union didn't commit to an overland Virginia campaign until McClellan's Peninsular Campaign fizzled out. Why they never tried something like that again is the bigger question than the Shenandoah Valley, IMO.
The failure of the Peninsula Campaign poisoned the idea of an amphibious invasion to take Richmond in the eyes of many Republicans. Many officers in the Army of the Potomac wanted to execute the Peninsula Campaign (particularly Sedgwick and John Gibbon), but it was politically impossible to execute.

In 1864, Grant initially recommended an invasion of North Carolina by transporting 60,000 men of the Army of the Potomac to Suffolk and marching them south to capture Weldon and Raleigh, and then march south again to capture Wilmington, the heart of Confederate logistics. However, the plan bore too much similarity to the Peninsula Campaign, 1864 was an election year with McClellan running for the Democrats, it would be best to avoid suggesting that McClellan's strategy in 1862 was the correct one.
 
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